The news deaf people have longed to hear

SCIENTISTS have developed the world's first surgically implantable hearing aid, which could end the misery suffered by thousands of people isolated by their deafness.

Five patients in Britain have received the device, which is implanted in the middle ear in a two-hour operation. Tests showed their hearing threshold was improved compared with the most expensive conventional devices on the market.

Fitzgerald O'Connor, consultant ear nose and throat surgeon at Guy's and St Thomas' hospital in London, who operated on three of the patients, said: "It is an ingenious device. It is a dramatic sea-change in the technology."

One in five patients with a conventional hearing aid never wears it because of soreness, blockage to the ear and problems with feedback. By implanting the device these problems are eliminated and hearing is improved.

The device, called a "vibrating sound bridge", consists of a tiny transducer the size of a pea which is attached to the three tiny bones in the middle ear that transmit the vibrations of the ear drum to the cochlea in the inner ear.

Unlike a hearing aid that takes sound and makes it louder in the external ear, the soundbridge takes sound and converts it to vibrations in the middle ear. The sound is conveyed to the transducer via an internal receiver placed just under the skin behind the ear. The receiver is magnetised and a small external microphone is worn attached to it on the side of the head. The microphone can be hidden under the hair so that the device is almost invisible.

It is different from a cochlear implant, which transmits electronic signals to the nerves of the inner ear, providing limited hearing to the profoundly deaf. The soundbridge is a substitute for an ordinary hearing aid used by the partially deaf.

The US manufacturers of the soundbridge, Symphonics, have patented an implantable microphone and say that within two years the whole device will be inserted in the head.

The five British patients - two were operated on in Birmingham - are among 47 who have received the device since last October in a Europe-wide trial. The Food and Drug Administration has not allowed the operations to go ahead in the US but approval was granted in Europe. Mr O'Connor said that although it required sophisticated surgery, the operation was not new .

"We have obtained ethical approval and done everything by the book. It was accepted because this is not new surgery but new technology."

He said the surgery cost pounds 4,000 to pounds 5,000, compared with conventional hearing aids ranging from pounds 50 to pounds 1,000. "It is potentially suitable for thousands of patients but whether it will be available on the NHS is a different kettle of fish. That is a problem for the NHS. I don't think it should stop one from developing new technology."

He added: "Our patients are very positive. Their hearing thresholds are generally better than with the best hearing aids we were able to get, which would cost pounds 1,000 in the high street. If it is successful we will start to use it in children."